1. Field of the Invention
An apparatus and method is disclosed for a reduced-capacity substrate carriers for use within an IC fab. Side-opening carriers with a capacity of fewer than the conventional 13 or 25 wafers may be constructed in a manner similar to the FOUP defined in SEMI E47, but characterized by reduced height and weight.
2. Brief Description of Related Developments
There is a move in the semiconductor industry to reduce wafer cycle time through the fab and reduce the amount of work in progress as well as to improve wafer safety. Studies have shown that by moving to a single wafer carrier, wafer cycle time and WIP is significantly reduced. In addition for the next generation wafer size (450 mm) the ITRS roadmap calls for single substrate carriers. Benefits of using single wafer or reduced capacity carriers include WIP reduction, process changeover time reduction and product ramp time improvement. Problems arise where single substrate carriers are employed relative to the ability of both the process tool and material transport system to effectively maintain the higher pace of the factory due to the larger number of carrier transport moves as compared to 13 or 25 wafer carriers. One example of such a problem includes where there is only one slot. It is desired that the robot in the process tool have the capability to quickly swap (fast swap) the wafer in the carrier so the carrier may be able to be replaced with another carrier that has an unprocessed wafer to keep the tool busy. Many such tools do not have the ability to fast swap, as in the case of a conventional single blade three axis robot. Another example of such a problem includes where there is only one slot. It is desired that the material transport system transporting carrier to tools in the IC FAB have the capability to supply carriers, at a high rate and quickly swap the carriers at the process tools load port(s) so that one carrier at the tool may be able to be replaced with another carrier that has an unprocessed wafer to keep the tool busy. Many such material transport systems do not have the ability to supply carriers at a high rate or with the capability to fast swap, as in the case of a conventional (overhead transport) OHT based material transport systems as implemented in conventional 300 mm fabs. Accordingly, there is a desire to provide a carrier and methods of using the carrier that facilitates the higher carrier move rates.
Examples of transport systems, carriers and openers may be found in U.S. Pat. Nos. 6,047,812; RE38,221 E; 6,461,094; 6,520,338; 6,726,429; 5,980,183; and United States Patent Publications 2004/0062633, 2004/0081546, 2004/0081545; 2004/0076496 all of which are incorporated by reference herein in their entirety.